In lung cancer, mediastinum lymphatic spread occurs. We review our technique and experience of thoracoscopic mediastinal lymphnode dissection (MLND). Between 1997 and 2011, 992 patients with primary lung cancer underwent thoracoscopic major pulmonary resection with MLND. Initially we used a combination of electrocautery and clips to divide blood vessels and lymphatic channels; our current technique relies on a vessel sealing system (VSS) which is expeditious and leads to less lymphorrhea. Furthermore, dissection of station 7 nodes is performed after each main bronchus or right intermediate bronchus is taped with a 0 silk suture, which is then brought out of the thorax through the access incision for antero-lateral retraction of the tracheal carina. We dissect between 3 and 4 N2 lymph node stations and a total of approximately 20 N2 lymph nodes. Postoperative complications related to MLND occurred in 35 of 992 patients (3.5%), 15 (1.5%) for recurrent laryngeal nerve injury, 3 (0.3%) for bilateral vagal injury, 14 (1.4%) for chylothorax and 3 (0.3%) for airway injury. However, none were lethal. Thoracoscopic mediastinal dissection is safe and feasible in treating lung cancer. We believe our technique and VSS are very useful for thoracoscopic MLND.